A bone scan is sometimes performed to rule out an inflammatory process (such as a tumor or infection) or an occult fracture (small fracture not seen on an x-ray).
A bone scan is performed by injecting a small amount of radioactive marker into an intravenous line (IV). Three hours later the patient is placed through a scanner and the radioactive marker will be concentrated in any region where there is high bone turnover.
A bone scan is a highly sensitive test to pick up tumors, infections, or very small fractures because these conditions all result in high bone turnover. It can also be used to determine if a compression fracture of the vertebral body is old or new, as an old fracture will not light up and a new one will.
Bone scans, however, cannot distinguish what a lesion represents, and therefore cannot differentiate between a tumor, an infection or a fracture. Therefore, this type of imaging study usually needs to be followed by a CT scan and/or MRI scan to better characterize the lesion.
